124 



GLASS HOUSES FOR VEGETABLE CROPS 



than was possible with hotbeds or coldframes or 

 with the form of greenhouses used in the early 

 days. 



The business of growing vegetable plants either 

 for sale or home use has assumed large proportions. 

 In some cases, the houses that have been used 

 for the growing of vegetables or ilowers are 

 used for this purpose, while in others spe- 

 cial houses are used. Although not 

 necessary, it will be convenient 

 to have raised benches in 

 houses to be used for 

 this purpose, at least 

 enough to serve as 

 seed-beds, other- 

 wise the vegeta- 

 ble houses will 

 answer very well. 

 Less care is re- 

 quired in the con- 

 struction of 

 houses to be used 

 exclusively for 

 the starting of 

 plants in the 

 spring. The roof covering of small houses can be 

 of hotbed sash, and the houses can be heated by 

 means of flues. 



Types of houses. 



The forcing-houses in use thirty years ago, and 

 which are occasionally found today, were about 

 ten feet in width, with wooden walls and the roof 

 covered with a row of hotbed sash on each side of 

 the ridge. They were commonly heated with a flue. 

 The width of the houses was gradually increased 

 to about twenty feet. (Fig. 179.) The walls were 

 either of posts covered with a double thickness 

 of boards, or there was a row of glass one to 

 two feet in width under the plates to furnish light 

 and ventilation. In addition to the two benches 

 about four feet wide found in narrow houses, these 

 contained a bed or bench through the center about 

 eight feet wide. While some of the houses of 

 this size were heated with flues, hot water was 

 more commonly used, although in large ranges 

 steam was generally preferred. This width and 

 style of house gives good satisfaction, and even 

 today will be found very well suited to the pur- 

 pose if only one or two small houses are required. 



The modern vegetable forcing-houses are more 

 commonly constructed of widths varying from 

 twenty-six to fifty or more feet, as it has been 

 found that better crops can be grown in the wide 



Fig. 180. A side-hill gieenhouse. 



houses and there will be less waste room. By 

 building the houses where there is a slight gradual 

 slope of the land toward the south, it is possible to 

 erect a house forty or fifty feet in width without 

 having the ridge excessively high, while the 

 amount of space lost along the south wall will 

 be much less than when three to five houses 

 are required to give the same area. (Fig. 

 180.) 



In addition to the ordinary form 

 of greenhouse with vertical 

 walls, a style that will 

 add eight to ten feet 

 to the available 

 width of the 

 house, without 

 greatly increas- 

 ing the cost of 

 construction or of 

 heating, is built 

 with a sort of hip- 

 roof ; that is, in- 

 stead of having 

 vertical walls, the 

 plates are sup- 

 ported by means of iron posts and the side walls 

 stand at an angle so that at the ground the walls 

 are three to five feel; outside of the plates on each 

 side of the house. 



If the houses are not sufficiently large to make 

 it worth while to drive in at the ends with compost, 

 there should be either ventilators or movable sash 

 in the side walls that can be taken out so that soil 

 can be thrown in. 



The most common form of roof for vegetable- 

 houses is the even span, with the houses running 

 either east and west or north and south. The three- 

 quarter-span houses, with the long slope either to 

 the south or to the north, are also much used. In the 

 former case, the north wall is usually somewhat 

 higher than the south, but if the long slope is to 

 the north the walls are of the same height. It is 

 possible to build a house fifty or more feet in width 

 under a single roof by placing it on a gentle slope. 

 As much as five-sixths of the roof may then be in 

 the south slope. 



I%e framework. 



There is considerable variety in the methods of 

 construction used for vegetable-houses, as indi- 

 cated in Figs. 179-183. , In some cases, posts of 

 cedar, or some other durable timber, are set at 

 intervals of six feet so as to stand five or six feet 

 above ground. They are then covered to the height 

 of two or three feet with sheathing and siding, 

 with a double thickness of building-paper between. 



. A sill is placed on this and the space up to the 

 plate is filled in with sash-bars and glass. Another 

 method is to build a wall of concrete to the height 

 of two feet. In this, two-inch gas-pipes are set 

 at intervals of five feet. These support the plate, 

 and the space between the plate and the concrete 



' is occupied by glass. In other cases, angle or flat 

 bar iron is used for the posts, to the upper ends of 

 which iron rafters are fastened. 



